This invention relates to beacons that radiate as an identification of the location of the beacon and more particularly to such beacons that are readily portable by an individual and identify the beacon location to friendly observers at a great distance.
Emergency lighting devices are sometimes portable and used to identify temporary military runways for fixed wing aircraft and landing areas for helicopters. These include battery powered marker lights that identify a runway and illuminators of a helicopter landing pad. For both of these, some light generating devices have projected infra-red light and the pilots who are guided by the light have been equipped with night vision goggles that detect infra-red and give the pilot a visible light image of the scene. There are several reasons for using infra-red radiation: (1) even low light levels of infra-red light can be seen several miles away by a pilot equipped with night vision goggles; (2) infra-red light is not obscured by visible lights; and (3) infra-red light cannot be seen except by pilots wearing night vision goggles and so is, therefore not visible to unfriendly pilots who do not have night vision goggles. In all cases, with such emergency lighting devices used by the military, the purpose is to identify an area on the ground to a pilot to aid the pilot to land his aircraft at that area.
Portable emergency beacons that identify an individuals location to the world have been used in many situations, including military. They are used by downed aircraft, ships and boats of all kinds and individuals. The purpose of all of these is to attract attention and so initiate a rescue. Some flash visible light, some transmit radio signals and many do both. They are designed to withstand water immersion, shock and heat and most contain an energy source, such as a long life battery. In all cases they radiate and/or transmit omni-directionally at all elevation angles and the purpose is to attract anyone and everyone.
Beacons that identify the location of friendly military personnel, on the other hand, are intended to attract only friendly observers and, above all, must avoid attracting unfriendly observers (the enemy). In that respect, such beacons are similar to the military lighting devices mentioned above that are used to identify temporary military runways for fixed wing aircraft and landing areas for helicopters. However, the purpose and function of beacons for identifying the location of friendly personnel is different from those aircraft landing aids.
It is an object of the present invention to provide a readily portable (by an individual) beacon that identifies the individual or his vehicle only to friendly observers.
It is another object of the present invention to provide such a beacon with a self contained power supply packaged and contained to withstand moisture and dirt and harsh ambient conditions.
It is another object of the present invention to provide such a beacon that transmits more than one type of radiation of different visibility that is predetermined to attract only friendly observers at substantially different ranges (distances), particularly at night.
It is another object of the present invention to provide such a beacon that is adjustable so that the radiation therefrom can be restricted to friendly directions.
It is another object of the present invention to provide such a beacon that is adjustable so that the radiation therefrom can be restricted to the direction of friendly aircraft at night or in dim ambient light.
It is another object of the present invention to provide such a beacon incorporating means indicating to friendly personnel in close proximity that the beacon is in operation.
It is another object of the present invention to provide such a beacon incorporating means for remotely controlling the beacon.